Device for heating tablets of resinous molding compositions



Nov. 26, 1940. FUCHS 2,223,034

DEVICE FOR HEATING TABLETS OF RESINOUS MOLDING COMPOSITIONS Filed Oct. '7, 1938 E /W i INVENTOR A /v row 1- ucv-w:

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Patented Nov. 26, 1940 UNITED STATES PATENT OFFICE DEVICE FOR HEATING TABLETS F RESIN- OUS MOLDING COMPOSITIONS Anton Fuchs, Nieder-Lausitz, Spremberg, Germany, assignor to H. Riimmler Aktiengesellschaft, Nieder-Lausitz, Spremberg, Germany, a corporation of Germany Application October 7, 1938, Serial No. 233,802 In Germany October 14, 1937 Claims. (Cl. 219-19) The invention relates to devices for heat treat- The device according to the invention contains ing tablets of resinous molding compositions pretwo metallic heating plates between which a narvious to the hot pressing of these compositions. row heating chamber is formed, the width of A known expedient for facilitating the hot which is just suflicient to allow inserting the 5 molding of resinous compositions consists in tabtablets to be preheated. A slidable frame strucleting or briquetting the composition, that, is, in ture resting on a support or table in front of the pre-shaping the material into the form of discs heating chamber is designed to be moved into -by the mere application of pressure. It is furthe heating chamber in order to transport the ther known to preheat resinous molding compotablets placed on the table into the chamber and sitions either as a powder or in the form of the to remove them from the chamber after the heat 10 above-mentioned tablets previous to the hot treatment is finished. Accordin o e i e pressing proper in order to shorten the time durtion, the above-mentioned table may be provided ing which the composition must be left in the with means for easily discharging the tablets into mold. The preheating treatment above referred a collecting container or the like after the tablets to is usually done by placing the composition in have been removed from the chamber. 15 heating chambers of relatively large volume with- On account of the fact that the heatin in which the heat is transferred to the resinous faces of the narrow chamber are arranged in substance mainly by heat radiation. Since with 01058 P o y o e e e pp y Of heat such a heating method an even increase of the from these surfaces to the tablets occurs considtemperatures throughout the interior of the suba ly mor rapid y and v l t in he own 20 stance cannot be relied upon, care must be exerdevices. Since the tablets while bein heated cised to prevent a local overheating of the subrest upon one of the heatin u a s, e at stance. Therefore, the temperature must b kept supplied by this surface is furnished to the tablet at a relatively low value so that the heating y heat v ty- Although t e heating 1- occurs slowly enough to ensure a gradual progress face above the tablets may be arranged a slight 25 of the reaction. Such a method is not only critdistance away from e top surface of the tabical, but may also have a disadvantageous infiulets, this distance is so small that the heat transence on the further working up of the material, fer, though Occurring by radiation, is Considerespecially on the products obtained by the final ably more effective than in the known voluminous hot molding of the resinous substance. preheating cabinets. In further contrast, to the 30 An object of the present invention is to av id known heating devices, the heat radiation from the drawbacks of the known devices for heating e pp heating Surface y e increased by resinous tablets or briquettes previous to the heating the upper a in p t m a the hot pressing proper. More particularly, the inlower plate. In this case it is possible to make vention aims at increasing the temperature of t e qu y 0 heat furnished from e pp 35 the pre-treatment and at diminishing the time heating surface virtually equal to the heat supnecessary for such treatment without impairing plied by conductivity from the lower surface on the desired qualities of the resinous composition. which the tablets rest.

Another object of the invention is to provide a However, the invention may also be realized by 49 preheating device of simple and reliable conmaking the distance between the heating plates struction. An object, further, is to obtain a simadjustable so that after having placed the tabple mode of operation of the heating device so lets in the heating cha the upper plate is that, for instance, .the person operating the presslowered until it touches the tablets. Now the ing machine or handling the press molds, has no transfer of heat from the upper heating plate also difficulty in also effecting the preheating of the is mainly by heat conductivity. Th dj ment tablets, if desired. I of the distance between the heating plates may The invention utilizes a conception gained be effected by hand or by means of a mechanical from numerous experiments according to which connection with the device for transporting the a considerable increase in the preheating temtablets from the aforementioned table into the perature is possible if the tablets are heated conheating chamber, so that only one operation is 50 ductively so as to assume this temperature rapidly necessary to feed the tablets to the heating device and evenly. It has been found that treating the and to bring the upper heating surface into contablets in this way allows reduction of the hot tact with the tablets. molding period and also improves the final The invention will more easily be understood product, from the following description of two embodi- 55 b and c.

ments of the invention illustrated'in the accompanying drawing, in which Fig. 1 illustrates a part-sectional front view of a heating device;

Fig. 2 shows the same device in a part-sectional side view,

Fig. 3 shows a partial top view of the device represented by Figs. 1 and 2, while Fig. 4 illustrates a part-sectional front view of a second embodiment in which the distance between the two heating plates is variable.

In all the figures identical reference characters are used for indicating similar elements.

The heating device illustrated by Figs. 1, 2 and 3, contains a base structure composed of a base plate a, two side walls a, and two sup-- porting arms a". Two metallic heating plates b and c are mounted on this base structure and are held in proper position relative to each other by means of side plates f mounted on plate c. Each of the two heating plates is provided with an electric heating unit, b and 0, respectively. The heating surfaces of the plates b and 0 face each other so that a narrow interstitial heating chamber d is formed which extends horizontally. The height of the heating chamber is only slightly greater than that of the tablets or briquettes to be heated. A table g is arranged in front of the heating chamber and has its supporting surface in alignment with the heating surface of the lower plate b. The table g is mounted on the base structure of the device by means of a hinge h so that it forms a flap which may be tilted downward, as shown in Fig. 2 by broken lines, in order to discharge the tablets from the table surface into a collecting container is. A frame e fitting into the narrow heating chamber is arranged in .such a way that it may be moved out of the heating chamber onto the table 9. A handle 1 journalled about stationary pivots i is connected with the frame e by means of two coupling rods 7 engaging a cross-bar I connected with the frame. When moving the handle 1' from the position shown in Fig. 2 by solid lines, into the position shown in the same figure by broken lines, the frame e is moved from the heating chamber onto the surface of the table g. The cross-bar I is slidably carried by the supporting arms a", as will be seen from Figs. 2 and 3, so that the frame e retains its position when the table 9 is tilted.

The heating device above described is operated as follows: While the table g is in the position shown in Fig. 2 by solid lines, the frame e is placed on the table in the position illustrated by broken lines. The tablets or briquettes to be preheated are placed on the table g so as to lie within the opening of the frame e. Now the handle 1 is moved into the position shown in Fig. 2 by solid lines, thereby passing the frame e and the tablets placed therein into the heating chamber between the metal plates After the heating treatment is finished, that is, after a certain time has elapsed, the handle 1' isreturned to its original position wherein the tablets again rest on the table 9. By now tilting the table g, the tablets are discharged therefrom.

As the above-described embodiment shows,

the device according to the invention consists of relatively few individual elements of simple and inexpensive construction. The. mode of op- In Fig. 2 one tablet is indicated by'r.

eration of the device is extremely simple so that no particular skill or care is necessary for executing the heat treatment.

The heating device illustrated inFlg. 4 has, in general, the same construction as the abovedescribed embodiment, except that the upper heating plate 0 is movably guided on two studs m and 12. allowing the plate to be raised or lowered in order to adjust the distance between the heating surfaces of the two plates. 'The raising or lowering may be effected by any suitable means; in Fig. 4 for instance, these means are represented by a member 0 connected with the upper plate 0 and an actuating lever 1) passing through an opening of the member 0. By actuating the lever, the plate 0 is moved upward or downward. The frame e and the tablets placed therein are moved into the heating chamber while the plate 0 is in raised position. Then the plate is lowered until it rests upon the frame e or upon stops having the height of the tablets to be heated. After the treatment is finished, the plate c is raised before the frame e is removed from the heating chamber.

I claim: a

1. A device for heating tablets of resinous molding compositions previous to the hotmolding operation, comprising .two heating plates each having a plane and continuous horizontal heating surface facing the horizontal heating surface of the other plate so as to form a narrow interstitial heating chamber, said heating plates being arranged to maintain during the heating operation a fixed distance of approximately the. height of the tablets to be heated, horizontal supporting means for receiving the tablets arranged adjacent to and in alignment with the heating surface of the lower heating plate, and intermittently operating transporting means movably arranged on said supporting means and designed for simultaneously moving a multitude of tablets onto' and off of said heating surface of said lower plate.

2. A device for heating tablets of resinous molding compositions previous to the hot-molding operation, comprising an upper heating plate and a lower heating plate having their heating surfaces facing each other at a distance slightly greater than the height of said tablets so as to form a narrow interstitial heating chamber,

each of said plates having an electric heating element designed to produce in said chamber a temperature below the final hardening temperature of said tablets, the heating element or said upper plate being adapted to heat the surface of said upper plate to a temperature higher than that of the surface of said lower plate, a

table for receiving said tablets arranged in front of said plates so as to have the'table surface in alignment with the heating surface of said-lowaaeaoes table arranged adjacent to and in alignment with the surface of the lower heating plate, a

slidable frame fitting into said heating chamher for moving said tablets from said table into saidchamber and vice versa, said table being tiltably mounted in order to discharge said tablets 4., A device for heating tablets of resinous molding compositions previous to the hot-molding operation, comprising two heating plaites each having a plane and continuous heating surface facing the heating surface of the other plate so as to form a horizontal interstitial heat ing chamber, said plates being arranged to maintain during the heating operation a constant distance, means for relatively adjusting said plates to adapt said distance to the height of said tablets, supporting means having a table surface in alignment with the heating surface 20 of the lower heating plate, and means for moving tablets from said table surface onto the heating surface of said lower plate.

5. A. device for heating tablets of resinous molding compositions previous to the hot-molding operation, having two horizontal heating surfaces facing each other so as to form an interstitial narrow heating chamber, means for relatively adjusting said plates to adapt-the distance between said heating surfaces to the height of the tablets to be heated, said means being designed for maintaining said distance constant during the heating operation, a table arranged adjacent to and in alignment with, the lower of said heating surfaces, a movable frame designed to move the tablets to be heated from said table onto said lower heating surface and vice versa, and means for permitting said table to be tilted in order to discharge said tablets,

ANTON FUCHS. 

